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No. 62: Mar-Apr 1989

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"When planetary scientists examine one kind of meteorite rich in iron, the H-chondrites, they find that the meteorites' ages do not spread evenly through time. Instead, the ages seem to cluster at 7 and 30 million years."

Astronomers have hitherto been content to attribute these clumped ages to collisions among the meteorites' parent bodies - the asteroids - which ply periodic orbits. However, S. Perlmutter and R.A. Muller, at Berkeley, point to the apparent 26- to 30-million-year periodicities of three terrestrial phenomena:

  1. Biological extinctions in the fossil record,
  2. Magnetic field reversals, and
  3. Terrestrial-crater ages.

Could there be a connection between the clumped meteorite ages and these terrestrial phenomena? Perlmutter and Muller propose that all of these phenomena are the consequence of periodic storms of comets that invade the inner solar system from the direction of the Oort Cloud of comets that purportedly hovers at the fringe of the solar system. These comets not only devastate the earth but also collide with the asteroids, knocking off those bits and pieces we call meteorites.

(Anonymous; "Do Meteorite Ages Tell of Comet Storms?" Astronomy, 17:12, January 1989.)

Comment. Unanswered above is the question of why comet storms should be periodic. One hypothesis is that Nemesis, the so-called Death Star, a dark companion of our sun, lurks out there, periodically nudging the Oort Cloud of comets, causing it to release some of its comets.

From Science Frontiers #62, MAR-APR 1989. 1989-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987